WO 99/57239 has already manifested a solid-state fermenter comprising at least two fermenter levels permeable to air and water and arranged above one another, which are connected with the walls of the container in such a way that neither air nor water can flow past on the side, there being a culture substrate on the fermenter levels for the micro-organisms to be cultivated and a cooling device being fitted under each level.
In use, this fermenter manifests a number of disadvantages.
1. The use of a cooling system in the form of cooling spirals for each individual fermenter level, which run below the levels and each have to be provided with a flow of coolant and with a coolant discharge from the outside through the fermenter wall, results in a high risk of contamination of the fermenter material with the coolant used for cooling. This risk of contamination is in particular to be put down to the fact that each cooling spiral must be connected with the coolant feed and discharge tubes outside the fermenter with the help of 2 connectors (for feed and discharge of the coolant). Leaks can come about on these connectors. The risk of the occurrence of said leaks increases as the number of fermenter levels increases. As a result of the connection pieces of the cooling system protruding into the fermenter from the outside (one feed and one discharge per fermenter level), the insertion of the fermenter levels thereunder is connected with difficulties. In insertion, they must either be held at an angle or have been provided with a recess in order to be lowered past the connections and into the lower part of the fermenter.
2. A further problem with the solid state fermenter described under WO 99/57239 is that the fermenter levels are placed on “rings or otherwise shaped devices” (Claim 4). These “rings or otherwise shaped devices” are provided with a heat-stable gasket. This is to prevent water or air flowing past the fermenter levels. However, these “rings or otherwise shaped devices” have the effect that the insertion of the level underneath them is connected with difficulties.
Therefore, the invention was based on the task of eliminating the said disadvantages of the solid-state fermenter claimed in WO 99/57239 by constructive alterations and enabling the use of large volumes.
This task is solved according to the invention described below. The essential features of the invention area                a new kind of cooling of the fermenter material and        a new kind of sealing of the fermenter levels to the fermenter wall.        